:root {
    /* Light Mode - Premium Japanese Aesthetic */
    --primary-navy: #1a2a40;
    --secondary-gold: #c5a059;
    --accent-red: #b03a2e;
    --bg-light: #f9f7f2;
    --card-bg: #ffffff;
    --text-main: #333333;
    --text-muted: #666666;
    --white: #ffffff;
    --header-bg: #ffffff;
    --border-color: #eeeeee;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --primary-navy: #7e9bb4;
    --secondary-gold: #d4b475;
    --accent-red: #e67e22;
    --bg-light: #121212;
    --card-bg: #1e1e1e;
    --text-main: #e0e0e0;
    --text-muted: #aaaaaa;
    --white: #1e1e1e;
    --header-bg: #1a1a1a;
    --border-color: #333333;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans JP', 'Hiragino Kaku Gothic ProN', 'Meiryo', sans-serif;
    background-color: var(--bg-light);
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
    transition: var(--transition);
}

header {
    background-color: var(--header-bg);
    box-shadow: var(--shadow);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: var(--transition);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-navy);
    text-decoration: none;
    letter-spacing: 1px;
}

.logo span {
    color: var(--secondary-gold);
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

nav ul li a {
    text-decoration: none;
    color: var(--text-main);
    font-weight: 500;
    transition: var(--transition);
}

nav ul li a:hover {
    color: var(--secondary-gold);
}

main {
    max-width: 1000px;
    margin: 3rem auto;
    padding: 0 1.5rem;
}

.hero {
    text-align: center;
    margin-bottom: 4rem;
}

.hero h1 {
    font-size: 2.5rem;
    color: var(--primary-navy);
    margin-bottom: 1rem;
}

.hero p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
    border-bottom: 4px solid transparent;
}

.card:hover {
    transform: translateY(-5px);
    border-color: var(--secondary-gold);
}

.card h2 {
    color: var(--primary-navy);
    margin-bottom: 1rem;
}

.btn {
    display: inline-block;
    padding: 0.8rem 2rem;
    background-color: var(--primary-navy);
    color: var(--white);
    text-decoration: none;
    border-radius: 6px;
    margin-top: 1.5rem;
    transition: var(--transition);
    font-weight: 600;
}

.btn:hover {
    background-color: var(--secondary-gold);
}

/* Tool Page Specific Styles */
.tool-container {
    background: var(--card-bg);
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

textarea {
    width: 100%;
    height: 150px;
    padding: 1rem;
    border: 2px solid var(--border-color);
    background-color: var(--bg-light);
    color: var(--text-main);
    border-radius: 8px;
    font-size: 1rem;
    margin-bottom: 1.5rem;
    resize: vertical;
}

.result-area {
    margin-top: 2rem;
    display: none;
}

.result-box {
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.result-label {
    font-weight: 700;
    color: var(--secondary-gold);
    display: block;
    margin-bottom: 0.5rem;
}

.copy-btn {
    float: right;
    cursor: pointer;
    background: none;
    border: 1px solid var(--secondary-gold);
    color: var(--secondary-gold);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
}

footer {
    text-align: center;
    padding: 3rem;
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 768px) {
    nav ul {
        display: none;
    }
}